Web transport apparatus

ABSTRACT

Web transport apparatus for positively driving a web having a soft and tacky emulsion surface when wet, through a processing bath by contacting only the rear web surface after the web is wet. The apparatus comprises a horizontally arranged fluid containing tank with a pair of input rolls disposed along one side of and above the tank which are arranged to form a nip to drive the web into the tank. A pair of horizontally spaced belt support rolls are horizontally disposed in the tank with the first belt support roll adjacent said input rolls and the second belt support roll being disposed adjacent the side of said tank opposite from the first belt support roll. A horizontal belt idler roll is disposed in the tank between the belt support rolls and has an upper surface disposed below the upper surfaces of the belt support rolls. A web-carrying endless belt member is disposed in the tank and extends substantially across the width thereof in one direction, and around the belt support rolls and the lower surface of the idler roll in the other direction. The belt member has sufficient slack in the length thereof so that the upper span may be depressed below the upper surfaces of the belt support rolls. A first fluid supply is disposed above the first belt support roll and is arranged to apply a curtain of activator fluid to the web on the upper surface of the belt. The belt cooperates with the ends of the tank to form a flow path between at least one edge of the belt and the tank. The flow path is arranged, with respect to the flow from the first fluid supply, to limit the flow from the top of the belt whereby a pool of liquid is formed on the top span of the belt and the weight of the liquid pool depresses the belt into driving engagement with the driven roll. A second fluid supply is disposed above the second belt support roll and is arranged to apply a curtain of wash-off fluid to the web beyond the end of the belt and outside of the tank.

' United States Patent 1 Bruno et al.

[54] WEB TRANSPORT APPARATUS [75] Inventors: Frederick H. Bruno; Raymond J. Camp; Thomas H. Farrell, all of Rochester, NY.

[73] Assignee: Eastman Kodak Rochester, N.Y.

22 Filed: March 18,1971

[21] Appl.No.: 125,840

Company,

Related US. Application Data [62] Division of Ser. No. 863,531, Oct. 3, 1969, Pat. No.

Primary Examiner--Samuel S. Matthews Assistant Examiner-Fred L. Braun AttorneyW. O. Hodsdon et al.

[5 7] ABSTRACT Web transport apparatus for positively driving a web having a soft and tacky emulsion surface when Wet through a processing bath by contacting on the rear 111 3,710,703 [4 1 Jan. 16, 1973 web surface after the web is wet. The apparatus comprises a horizontally arranged fluid containing tank with a pair of input rolls disposed along one side of and above the tank which are arranged to form a nip to drive the web into the tank. A pair of horizontally spaced belt support rolls are horizontally disposed in the tank with the first belt support roll adjacent said input rolls and the second belt support roll being disposed adjacent the side of said tank opposite from the first belt support roll. A horizontal belt idler roll is disposed in the tank between the belt support rolls and has an upper surface disposed below the upper surfaces of the belt support rolls. A web-carrying endless belt member is disposed in the tank and extends substantially across the width thereof in one direction, and around the belt support rolls and the lower surface of the idler roll in the other direction. The belt member has sufficient slack in the length thereof so that the upper span may be depressed below the upper surfaces of the belt support rolls. A first fluid supply is disposed above the first belt support roll and is arranged to apply a curtain of activator fluid to the web on the upper surface of the belt. The belt cooperates with the ends of the tank to form a flow path between at least one edge of the belt and the tank. The flow path is arranged, with respect to the flow from the first fluid supply, to limit the flow from the top of the belt whereby a pool of liquid is formed on the top span of the belt and the weight of the liquid pool depresses the belt into driving engagement with the driven roll. A second supply is disposed above the second belt support roll and is arranged to apply a curtain of wash-off fluid to the web beyond the end of the belt and outside of the tank.

1 Claim, 3 Drawing Figures PATENTEDJAN 16 I975 I III/I7 [LL/III was TRANSPORT APPARATUS This application is a division of U.S. Pat. application, Ser. No. 863,531, filed Oct. 3, 1969, now U.S. Pat. No. 3,630,213.

BACKGROUND OF THE INVENTION Many products have been developed for use in engineering and architectural drawing reproduction. One such graphic arts product that has found acceptance in this field is a photo-graphic film or paper utilizing a wash-off emulsion such as disclosed in U.S. Pat. No. 2,592,368. With this product, the drawing is exposed onto the emulsion surface and the film is passed through a developing or tanning agent which hardens the image area exposed on the emulsion. Thereafter the unexposed emulsion is easily washed off by a water spray leaving only the hardened image-carrying portion of the emulsion. These products have gained widespread acceptance because of the ease of processing, requiring only a single developing agent and a wash-off spray of warm water. Also these products are desirable because they are available in very large sizes, e.g., 42 inches wide by feet or more long. Moreover, these products are advantageous because of the dimensional stability thereof which is exceeded only by glass plate products. Since only the image contains emulsion, only a very small portion of the surface of the film is susceptible to variations in humidity, etc. which can result in variations in the dimensions of the final drawing. Moreover, these products have been widely accepted because, while providing stable, permanent images they are relatively easily corrected, requiring only moistening of the image and removal thereof with a nonnal eraser. Thereafter, that portion of the image may be changed or corrected by normal drafting procedures, without requiring the complete redrafting of the entire drawing.

While these drawing reproduction products have been widely accepted because of the foregoing advantages they are susceptible to damage in handling, especially during the initial stages of the image activation. It has-been found that when the image is initially subjected to the activating developing agent, the entire emulsion layer softens whereby it is subject to damage by abrasion or emulsion peel-off, at least until' the image portion has been sufficiently hardened by the activator solution. Thereafter, the image area is substantially immune to damage from abrasion but the unexposed portion of the emulsion layer must be removed by water sprays or a combination of water sprays and scrubbing. It has been found that the emulsion removed by the water sprays tends to collect on any contacting surface and soon builds up to an undesirable extent. As a result, successful automatic processors capable of handling these products have not been developed. The normal procedure for processing these products has been to immerse the entire sheet containing the exposed image into a tank and to then pour the activator solution over the emulsion surface ofsthe film. After sufficient time has elapsed to harden the image area, the film is removed from the activator tank and is transported, usually by hand, to a wash-off tank where a spray of water is applied to the emulsion and the unexposed emulsion is removed by the spray and/or hand scrubbing with a softbrush. Whenfilm having dimensions such as those set forth above is to be processed by hand, it will be appreciated that quite large tanks are necessary and several men will be required to apply the activator, transport the sheet to the wash-off tank, and to scrub the soft unexposed emulsion from the surface of the film. Not only is such an operation costly and time consuming, but it is sloppy and can give inconsistent results due to the variations in the manner in which it is handled. Moreover, the length of time the emulsion is exposed to the developing agent and the degree of softened emulsion removal can vary with the operator.

Heretofore, attempts to construct an automatic processor for handling such wash-off film products have been generally unsuccessful due to the fact that most such apparatus utilize a roller transport to move the exposed film through the processing stations. Because of the extremely soft nature of the unexposed portion of the wet emulsion, the emulsion can be easily picked up by the transport rollers, creating severe emulsion build-up and cleanliness problems. Even attempts to contact the surface of the emulsion with rollers having a non-sticking, Teflon surface have been generally unsuccessful.

Accordingly, it will be appreciated that automatic apparatus for processing and handling wash-off emulsion film is extremely desirable in providing consistent results if the emulsion build-up and cleanliness problems can be solved. With such automatic apparatus, damage to the emulsion surface can be substantially eliminated, the number of operators necessary to handle the film should be substantially reduced, and consistent timing of the emulsion activation should be accomplished.

SUMMARY OF THE INVENTION Accordingly, the present invention provides apparatus for processing wash-off emulsion type films and papers whereby the film is transported through the activator solution by a web transport belt which contacts only the rear surface of the film. The belt is loosely arranged over a pair of belt support rolls and has a length such that the upper surface of the belt sags therebetween. Means is provided for driving at least one belt support roll. Activator fluid is supplied to the upper surface of the belt and forms a pool in the center depressed portion of the belt between the belt support rolls. The weight of the activator solution on the belt tightens the belt about the belt support rolls so that it is driven thereby. At the same time, the pool of activator solution provided on the upper surface of the belt, which is maintained by the close proximity of the sides of the processor tank with the edges of the belt, completely wets the emulsion of the film being carried by the belt. The depth of the pool of the activator fluid on the top surface of the belt and the speed of the belt, as determined by the speed of the driven rolls, controls the length of time the emulsion is exposed to the activator solution.

Moreover, the activator fluid provides a capillary action between the belt and the back surface of the film so that the film is positively drawn alongwith the belt. Thus the film is positively driven by the belt with no belts or rolls contacting the soft wet emulsion surface of the film. The film is driven up out of the pool of activator fluid by the belt approaching the second belt support roll and, because of the short radius of curvature of the belt over the second belt support roll, tends to travel in a straight path, breaking the capillary action holding the film to the belt after the film passes over the second belt support roll. As the film leaves the belt, it passes beneath a water spray which both removes a portion of the softened unexposed emulsion and directs the film to a wash-off station where the remaining portion of the unhardened emulsion may be removed.

Accordingly, the present invention provides a web transport apparatus for moving a web through a liquid bath by contacting only one web surface. The apparatus comprises a fluid-containing tank having a pair of horizontally v spaced rolls horizontally disposed therein with thefirst roll adjacent one side of the tank. A web-carrying endless belt member is disposed in the tank and extends substantially across the width thereof. The endless belt member has a length greater than twice the distance between the rolls whereby it is loosely supported by the rolls. Means is provided for driving at least one of the belt support rolls. Means is provided for depressing the upper span of the belt into driving engagement with the driven roll. Fluid supply means is disposed above the first roll and is arranged to apply a curtain of fluid to the web on the upper surface of the belt. A second fluid supply means is disposed above the second roll and is arranged to apply a curtain of fluid to the web beyond the end of the belt.

More specifically, the present invention provides a web transport apparatus for positively driving a web through a processing bath by contacting only the lower web surface after the web is wet. The apparatus comprises a horizontally arranged fluid-containing tank having a pair of input rolls disposed along one side of and above the tank, which input rolls are arranged to form a nip to drive the dry web into the tank. A pair of horizontally spaced belt support rolls are horizontally disposed in the tank with the first belt support roll adjacent the inlet rolls. The second belt support roll is disposed adjacent the side of the tank opposite from the first belt support roll. A horizontal belt idler roll is disposed in the tank between the drive rolls and has an upper surface disposed below the upper surfaces of the beltsupport rolls. Means is provided for driving at least one of the belt support rolls. A web-carrying endless belt member is disposed in the tank and extends substantially across the'width thereof. The endless belt member extends around the belt support and the lower surface of the idler roll in the tank and has sufficient slack therein that the upper span may be depressed into contact with the upper surface of the idler roll. First fluid supply means is disposed above the first belt support roll and is arranged to apply a curtain of activator fluid to the web on the upper surface of the belt. A second fluid supply means is disposed above the second belt support roll and is arranged to apply a curtain of wash-off fluid to the web beyond the end of the belt outside of the tank. And means is provided outside the tank adjacent the second belt support roll for washing and drying the web.

The various features of novelty which characterize the present invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and the specific objects obtained by its use, reference should be had to the accompanying drawing and descriptive matter in which a preferred embodiment of the present invention is illustrated and described.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic elevation of a preferred embodiment of the present invention;

FIG. 2 is a cross section taken along line 22 of FIG. 1; and

FIG. 3 is a schematic elevation of an alternative embodiment of the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT A schematic side elevation of a preferred embodiment of the present invention is illustrated in FIG. I and comprises a horizontally disposed fluid-tight tank 10 having a substantially open upper side. In the embodiment illustrated, the tank has a width sufficiently great that a sufficiently wide web can be handled thereby and a length sufficient to permit the desired activation time of the web in the tank at the speed (which may be fixed or variable) of web transport therethrough. A pair of horizontally arranged input rolls l2 and 14' are arranged above and along one side of the tank 10 and form a nip arranged to feed an exposed, emulsion-coated web 16 into the processing tank 10. A pair of horizontally disposed belt support rolls 18 and 20 are disposed within the tank 10 and extend substantially across the width thereof with the first roll 18 disposed along the same side of tank 10 as, and adjacent inlet rolls l2 and 14. The second belt support roll 20 is parallel to and horizontally spaced from the first belt support roll 18 and extends along the opposite side of tank 10. A drive means, not shown, is arranged to drive either or both of rolls 18 and 20. A horizontally disposed idler roll 22 is arranged within tank 10 between and parallel to belt support rolls l8 and 20. The idler roll is disposed in the tank beneath belt support rolls l8 and 20 so that the upper surface of the idler roll is below the upper surface of rolls l8 and 20.

An endless web-transport belt 24 is disposed within tank 10 and extends around rolls 18, 20 and 22. The width of the belt 24 is substantially equal to, but somewhat less than the width of the tank so that a small space is formed between the edge of the belt and at least one of the end walls of the tank. The length of the belt is substantially greater than twice the distance between belt support rolls l8 and 20 so that, when extending around the drive rolls with the lower span of the belt passing beneath the idler roll 22, the upper span of belt 24 has sufficient slack therein between rolls l8 and 20 that it can be depressed into contact with the upper surface of idler roll 22, and the belt will grip belt support rolls I8 and 20 sufficiently to be driven thereby.

An activator fluid supply manifold 26 extends across one side of tank 10 above the first belt support roll 18. The supply manifold 26 is provided with a plurality of orifices whereby a substantially solid film or curtain of activator fluid is applied to the upper surface of the belt 24 passing over roll 18 and to the upper surface of any web fed through input rolls l2 and 14 and carried by .the belt. A plate member 28 depends downwardly from manifold 26 to aid in the formation of a curtain of activator fluid and to ensure that the entire surface of the web is wet simultaneously. In the embodiment illustrated, the manifold is supplied with activator fluid via pipe 30 and pump 32 from the bottom of the tank 10. Alternatively, the activator supply manifold may be supplied from a separate source of activator fluid (not shown) and the tank drained to waste, with no recirculation of the activator fluid occurring.

A conventional web-washing conveyor belt 34 is arranged adjacent the side of tank and drive roll to accept the web as it leaves the activator tank. A plurality of water supply manifolds 36 are disposed across the wash-off belt 34 to supply sufficient quantities of water to wash the unexposed, unhardened emulsion from the surface of the film. The wash-off water, containing the softened emulsion, is collected in drain pan 38 for disposal.

In operation, the exposed, emulsion-bearing film or paper web (which term is intended to include both individual sheets as well as indeterminate lengths of a web) is fed between input rolls l2 and 14 into the processing tank 10. As the leading end of the web 16 leaves rolls l2 and 14 it is contacted by the film or curtain of activator fluid from supply manifold 26 and is forced into contact with the upper surface of the belt 24-at roll 18. The activator fluid also wets the upper surface of the belt so that a capillary force is created between the upper surface of the belt and the lower surface of the web holding the web to the belt whereby the web is positively driven by the belt. This capillary force is sufficiently great that the web will be driven by the belt even though only one end portion is in contact with the belt. As previously noted, the belt has a width somewhat less than the width of the processing tank 10 whereby the fluid flowing into the processor tank from the inlet manifold 26 is introduced at such a rate that the space between the edge of the belt and the inner surface of the tank wall prevents the activator fluid from draining from the surface of the belt at the same rate it is fed from the activator manifold. Thus, a pool of fluid 40 is formed on the upper surface of the belt whose depth is regulated by the relative flow rates of the space between the side of the belt and the tank wall and the rate at which the supply manifold supplies the activator fluid. The weight of this pool of liquid depresses the upper span of the belt until the belt is taut between rolls l8 and 20 and in contact with the idler roll 22. Accordingly, the belt 24 is in driving contact with the driven roll, 18 or 20. Moreover, the pool of activator liquid assures that the entire emulsion surface of the web is contacted by activator solution and, in combination with the drive speed of belt 24, operates to control the time the emulsion is in contact with the activator fluid. Accordingly, the web is positively driven through the activator fluid by the belt 24 and is driven up the sloping outlet side of the belt towards roll 20, all without touching the emulsion surface of the web. At roll 20, the radius of the curvature of belt 24 is sufficiently small that the capillary action between the surface of the belt and the surface of the web is broken and the rigidity of the web causes the web to continue in a substantially straight line. Shortly after extending beyond roll 20, the web is contacted by the curtain of wash water supplied by the first water supply manifold 36. The force of this water causes the web to deflect into contact with the wash-off belt 34 to be moved along the wash-off path beneath the water supply manifolds 36. By the time the web reaches the end of the wash-off conveyor 34, all of the unhardened unexposed emulsion has been removed from the surface of the web. lnasmuch as the emulsion removed by the wash-off water sprays is substantially diluted, there is little or no problem of emulsion build-up on the washoff conveyor. At this point, the web can be passed to a conventional film dryer with no danger of injuring the image surface of the film. Moreover, since all of the softened, unexposed emulsion has been removed there is no further danger of contaminating the transport apparatus and a conventional web dryer and transport (not shown) may be utilized.

An alternate embodiment of the present invention is illustrated in FIG. 3 wherein the present web transport apparatus is arranged for cooperation with the Kodak Supennatic processor 44. ln this illustration, the elements of the present invention are given the same reference numerals as in FlGS. 1 and 2 with the added prefix l." The Supermatic processor is arranged for processing film or paper products having different surface characteristics than the wash-off products handled by the present invention. Those products are fed into the Supermatic processor through feed rolls 46, through a developer station 48 and a fixer station 50. Thereafter, the product is turned, by means of rolls 52, and passes through a wash station 54 and a dryer station 56 to the outlet of the processor at 58. While the Supermatic processor is arranged for processing entirely different photographic products, an extremely advantageous combination can be obtained by connecting the web transport apparatus of the present invention to the rear of the Supermatic processor, whereby the web leaving the belt support roll is fed directly into the turning rolls 52 of the Supermatic processor, to be fed through the wash station 54 and dryer station 56. With this arrangement, a separate wash-off conveyor and a web dryer is not necessary for the apparatus of the present invention. It will be noted that, as illustrated, the wash-off water supply manifold 136 is arranged to deflect the web leaving roller 120 down a guide 60 to the turning rolls 52. By the time the web reaches turning rolls 52, a major portion of the softened emulsion has been removed from the surface of the web so there is no problem of emulsion build-up on the turning rolls 52. With such a construction, it is possible for the capability of a Supermatic or other similar processor to be significantly increased by merely adding the web transport apparatus of the present invention without significantly increasing the space required or the investment necessary. With this combination, a graphic arts processor is possible having a versatility not heretofore possible.

While preferred embodiments have been illustrated above, it will be appreciated that variations may be made in the specific structure of the present apparatus. For example, the idler roll 22 can be replaced by a shoe-member or other guide to provide space for the depression of the upper span of the belt. Alternatively, sufficiently large diameter belt support rolls 18 and 20 may be utilized that an idler roll or guide is not required to provide a sufficiently deep activator pool 40.

Similarly, while the level control of the pool on the upper span of the belt has been disclosed as being controlled merely by'the ,spacing between the edges of the belt and the ends of the tank, secondary baffles can be arranged at the edges of the belt for flow control. Furthermore, overflow openings may be provided in the walls adjacent the edges of the belt. These overflow openings can be arranged above the desired pool level, whereby the activator fluid overflows when the pool is too deep, or they can be arranged below the desired depressed position of the belt so that, upon the accumulation of excess fluid on the belt, the belt is depressed below the openings permitting the escape of the excess fluid.

It will thus be seen that the present invention provides asimple, effective web transport and processing apparatus for handling and processing wash-off emulsion films and papers which substantially eliminate the possibility of damage to the soft emulsion during the early stages of activation while, at the same time, eliminating emulsion build-up and cleanliness problems heretofore associated with the processing of such products. At the same time, consistency of processing results is substantially increased while at the same time simplifying and reducing the labor required in handling the product, resulting in substantial economies.

being disposed adjacent the side of said tank opposite from said first support roll, a horizontal belt idler roll disposed in said tank between said support rolls and having an upper surface disposed below the upper surfaces of said support rolls, means for driving at least one of said belt support rolls, a web-carrying endless belt member disposed inrsaid tank and extending substantially across the width thereof, said endless belt member extending around said belt support rolls and the lower surface of the idler roll in said tank and having sufficient slack therein that the upper span may be depressed into contact with the upper surface of said idler roll, first fluid supply means disposed above the first belt support roll and arranged to apply a curtain of activator fluid to the web on the upper surface of said belt, said belt cooperating with the end of said tank to form a flow path between atleast one edge of the belt and the tank, said flow path arranged with respect to the flow from said first fluid supply means to limit the flowfromthe top of the belt whereby a pool of liquid is formed on the top span of the belt, the weight of said liquid pool depressing the belt and tensioning it into drlvmg engagement with said at least one driven sup- 

1. Web processing apparatus which positively drives a web through a processing bath by contacting only the lower web surface after the web is wet, said web having an upper surface which is soft and tacky when wet, said apparatus comprising a horizontally arranged fluid-containing tank, a pair of input rolls disposed along one side of and above said tank which input rolls are arranged to form a nip to drive the dry web into the tank, a pair of horizontally spaced belt support rolls horizontally disposed in said tank with the first belt support roll adjacent said input rolls, the second belt support roll being disposed adjacent the side of said tank opposite from said first support roll, a horizontal belt idler roll disposed in said tank between said support rolls and having an upper surface disposed below the upper surfaces of said support rolls, means for driving at least one of said belt support rolls, a webcarrying endless belt member disposed in said tank and extending substantially across the width thereof, said endless belt member extending around said belt support rolls and the lower surface of the idler roll in said tank and having sufficient slack therein that the upper span may be depressed into contact with the upper surface of said idler roll, first fluid supply means disposed above the first belt support roll and arranged to apply a curtain of activator fluid to the web on the upper surface of said belt, said belt cooperating with the end of said tank to form a flow path between at least one edge of the belt and the tank, said flow path arranged with respect to the flow from said first fluid supply means to limit the flow from the top of the belt whereby a pool of liquid is formed on the top span of the belt, the weight of said liquid pool depressing the belt and tensioning it into driving engagement with said at least one driven support roll, second fluid supply means disposed above the second belt support roll and arranged to apply a curtain of wash-off fluid to the web beyond the end of said belt and outside of said tank, and means outside said tank for drying said web. 